Virtual phase distribution algorithm for non-invasive PD measurement techniques

Non-invasive techniques allow the detection of partial discharges without the need for electrical connection to the system. This approach has advantages in terms of health and safety and costs, but disadvantages in terms of sensitivity and ability to produce phase resolved analysis. This paper describes initial investigations made into the development of a non-intrusive wide band PD measurement system, together with the quasi real-time intelligent algorithm, which enables discrimination between power system partial discharge faults and other sources of impulsive radio noise in the RF spectrum. A statistical analytical process based on the combination of variables extracted from the frequency, phase and time domain representations of the signal is used to determine partial discharge characteristics. The system has been tested and verified under varying conditions.